The two did reconcile a few seasons later, and had their fifth child, but we don’t know if they’ll still be married when we see Stabler again.
Even though Stabler and Kathy had their share of marital problems, with her getting fed up with the stress involved in being married to a cop and leaving him in Season 6 of SVU.
I can only imagine, though, that if Kathy somehow got caught in the crossfire of organized crime dealings and it led to her death, whether still with her or not, that it would be enough to send him back to the force and leave him feeling very guilty about not being able to protect her.